Aircraft typically have one or more flaps movably attached to a trailing edge of a fixed wing structure. Such trailing edge wing flaps perform two functions: (a) to provide a high lift-to-drag ratio take-off configuration, and (b) to provide a high lift coefficient landing configuration. A high lift-to-drag ratio for take-off can be accomplished by trailing edge wing flap positions with (a) high Fowler motion (i.e. aft motion which increases wing projected area), (b) a single short and converging slot and, (c) a small flap deflection angle. The high lift coefficient for landing requires (a) high Fowler motion, (b) a short converging slot between the flap and the wing (and two such slots for double slotted flap configuration) and, (c) high flap deflection angles. Theoretically, the best Fowler motion versus flap deflection angle progression would be that the flap would initially move rearward with little or no rotation, and at the end of its rearward travel deflect downwardly for the landing configuration. A flap support structure that approaches this motion as closely as possible is the most desirable.
Many different flap support structures have been developed to guide and drive a trailing edge wing flap between its stowed and take-off and landing configurations, most of which incorporate a number of complex mechanical linkages. Such flap support structures are typically located on an undersurface of the flaps and therefore extend into the airstream below the lower aft edge of the wing, causing undesirable drag. Airplane performance is enhanced through minimizing drag, which can be directly correlated to a dollar saving for the airplane operator. To reduce drag, flap support structures are covered with an aerodynamic fairing, which is attached to the undersurfaces of the wing and the flap. To further minimize drag, it is desirable that the fairing exhibit a small and narrow cross-sectional area (i.e., the projected fairing area in a streamwise direction). Aerodynamic fairings having a narrow cross-sectional area are a feature of the outboard flaps on a Boeing 777X aircraft. To achieve the narrow fairing, the flap hinge fitting that connects the flap to the trailing edge of the Boeing 777X wing is cranked to result in an attachment footprint on the undersurface of the flap that is bent to remain within the narrow fairing loft and includes a number of tension joints, inefficient load paths and associated increased weight and manufacturing complexity.
There is a need in the art for improved support structures for deploying trailing edge wing flaps that have a simple, lighter weight structure with more efficient load paths and a smaller attachment footprint on the undersurfaces of the wing and the flap to permit use of aerodynamic fairings having a narrow cross-sectional area, to minimize drag and provide other advantages over known configurations, structures and methods.